Battling Invasive Tree Roots

by OCMGA Master Gardener Tammy Borden

When I moved to the country and a home surrounded by beautiful, mature trees, I was thrilled at the prospect of filling each corner and pathway with beautiful woodland perennials. I thought I found my paradise for growing what had become my obsession — hostas. What could be better for growing this tough, shade-loving perennial than towering trees that provided high, filtered shade? So, with shovel in hand, I began digging. In some areas, the soil was a beautiful, rich loam. But, to my surprise, I had difficulty slicing through the ground with my spade in some locations. While the soil was still beautiful, there was a mass of fibrous roots. Despite my concern, I decided to plant my beautiful established hostas that I brought from my previous home.


Within two years they shrank to one-third their size in the new location. The competition from the tree roots was too much for my beloved hosta to endure. Through the years I became accustomed to this battle in certain areas of my yard and have made adjustments with some success. Here are a few tips that will hopefully help if you battle a similar problem.


Container Gardening


Cobalt blue containers make a beautiful counterpoint to the hosta leaves

I have a new fondness for hostas in containers. I am especially fond of cobalt blue containers, which contrast beautifully with the many shades of hosta leaves. I am overjoyed at the results. If you choose to plant hostas in containers, make sure you give
them enough room, keep them well-watered, and after they have died back in the fall, bring them into your garage. I had some hostas double in size in one season using this method. I love placing them out in the garden among other perennials. The added height and color of the containers adds interest and a great focal point.


Where I’m determined to plant hostas in the ground in competitive root situations, I have resorted to planting them in two gallon (or more) black plastic pots and burying them right in the ground. I left several in the ground over winter and they came up beautifully this spring. Obviously, this can eventually limit the size of your plant, so bury as large of a pot as you can and plan to lift it out every few years to divide. There are large pliable mesh containers used in the nursery trade that are coated with copper hydroxide on the inside. The chemical regulates and deters roots growth of the nursery stock planted inside the pot. When hostas are planted in containers that are turned inside-out (so the coating is on the outside), exterior roots from surrounding plants and trees are deterred from penetrating the mesh. Some online forums rave about this method and I hope to trial it this year.

Planting the Right Tree

If you plan on planting a tree with the hopes of beautiful perennials beneath its shady canopy, keep the following good and bad in mind.

The Good: Top picks for friendly tree roots
• Oak – White, Pin, Burr, and other varieties
• Ash – although the threat of the Emerald Ash Borer makes this a futile choice
• Japanese Maple
• Magnolia
• Shagbark Hickory
• Japanese Chestnut
• Ginkgo
• European Larch
• Japanese Tree Lilac
• Crabapple
• Pagoda Dogwood
• Honey Locust

The Bad: Trees with invasive tree roots • Box Elder
• Maple – Silver, Norway, and Red
• River Birch

• Beech
• Hackberry • Spruce

If You Can’t Beat ’em, Join ’em

In some locations in my yard, I have become resigned to the fact that I cannot grow hostas. I have dug them out and relocated them to a friendlier location. Rather than abandon the perennial bed completely, I have found some plants that seem to coexist with those pesky roots. While these varieties don’t thrive, they do well enough to warrant their placement:


• Japanese Painted Fern
• Lady in Red Fern
• Brunnera
• Lamium (ground cover)
• Sweet Woodruff (ground cover) • Perennial Geranium


Give some of these techniques and recommendations a try. I’m still battling in some areas, but I’m determined to win!



By OCMGA Master Gardener Steve Schultz (article originally appeared in our Fall 2015 newsletter

“The fattest and most scrumptious of all flowers, a rare fusion of fluff and majesty,” wrote garden writer Henry Mitchell. Of course, he was speaking about my obsession, the peony! I’ve lost count of the different peonies in my garden, but my guess would be that I have about 25 the last time I looked. And yes, I found a ragged Coral Charm peony at Lowe’s last week that cried for me to take it home. Now I have to find that open area to plant it. That could be a bit difficult.

As we come to the fall of the year, there are often questions about seasonal care. The care really depends on the type of peony you have.

If you have the type of peonies that your great grandmother grew, it is probably an herbaceous peony. In short, it dies completely to the ground each winter. After the first killing frost, you can clean up these peonies with your clippers. I leave about three inches showing so I know where they are in the garden. I have also left the dead foliage until spring and all seems fine. The only time you really want to get rid of the foliage is when you have any kinds of mildew during the summer. Then it’s important to dispose of the foliage to prevent the spread of the mildew. Do not compost or you will simply perpetuate the problem!


Steve’s Bartzella peony


Do you have intersectional peonies such as Bartzella? These are a cross with herbaceous and tree peonies. The care is identical to that of the herbaceous peonies. Simply remove the dead foliage and in spring you will see all new growth coming out of the ground. 

Tree peonies have an entirely different kind of care. Do not cut them to the ground in the fall! Their leaves, buds and flowers come off the woody stems. I wait until spring to remove any stems that seem dead. This will be obvious because they will have no leaves and will look dried out. I also put chicken wire frames and mulch around my tree peonies right before the first snowfall or below zero temps. I think that the rabbits would love a mid-winter snack and I’m not go- ing to oblige them!

Taking care of your peonies this fall will prepare them for a nice nap this winter so you can rejoice in their beauty this spring!

Some of Steve’s peonies

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Golden Glow


At my house, golden barberry snuggled up next to a purple barberry

It’s a look that can easily be overdone, but plants with golden foliage do make striking accents when paired with contrasts like purple smokebush, sand cherry, or the black-green needles of deeply colored evergreens. In theory, they’re also wonderful for lighting up dark corners, but in practice they usually need full sun to keep their sunny color. Planted in shade they tend to fade toward bright green.

With that caveat in mind, go forth and shop! For year-round effect, there are evergreens. From arborvitae through spruces to yews, most of them come in evergold as well. The genera Chamaecyparis and Juniperus are particularly rich in gold-foliage cultivars, with offerings from several different species and a large assortment of sizes, shapes, and degrees of hardiness.

Among deciduous shrubs, you can choose from golden alder (Alnus incana ‘Aureus’), golden elder (Sambucus canadensis ‘Aurea’), golden Japanese barberry (Berberis thunbergii ‘Aurea’), golden mock orange (Philadelphus coronarius ‘Aureus’), and yes, you are seeing a pattern. If it says ‘Aureus’ or ‘Aurea,’ something about that plant is going to be yellow.

There is also a golden ninebark (Physocarpus opulifolius ‘Dart’s Gold’), golden privet (Ligustrum x vicaryi), several spireas including the pink-flowered ‘Gold Mound,’ and if you want to go all out, yellow-berry cranberrybush (Viburnum opulus ‘Xanthocarpum’), which has golden twigs and berries as well as golden leaves.

Rock that Garden

forest-rock-garden-imagesWhen walking through professional designed botanical gardens, you almost always see at least one and sometimes multiple rock gardens. They’re so beautiful and you might want to incorporate one of your own. “First, you should be aware that rock garden plants demand perfect drainage,” says Lawrence B. Thomas, of the North American Rock Garden Society. (His own rock garden is on an eleventh-floor terrace.) “To achieve good drainage, you should incorporate copious amounts of chicken grit or perlite into your soil.”

Once the soil is ready, and assuming you have good sun, some easily grown species suggested by Mr. Thomas are Androsace sarmentosa, which has clusters of pink spring flowers on short stems; American bluets, also called Quaker ladies (Houstonia caerulea), which sow their own graceful pale blue-flowered progeny in unexpected places; Draba rigida, a mustard family member that forms tight mats and bears brilliant yellow flowers in early spring; and Saxifraga cotyledon, which forms tight mats of small silver-edged leaves.

Other compact, easily grown favorites include creeping baby’s breath (Gypsophila

PM123242 Optimized

Beautiful little bellflowers

repens), whose multitudes of dainty pink flowers last for many weeks through late spring; candytuft (Iberis sempervirens), which has mounds of white spring flowers; the Carpathian bellflower (Campanula carpatica), whose violet-blue blooms last through much of the summer; and the yellow flax (Linum capitatum), which freely bears its bright sunny flowers in late spring.

A Shovel by Any Other Name…

18l8wp6zl0z9cjpgGo into your local home improvement or hardware store and ask for a shovel. Warning: you’d better know the task that you intend to tackle before the clerk can help you pick the appropriate tool. As gardeners, it’s important to take really good care of your equipment, but it’s equally important to pick the right equipment to begin with.

Thank you to OCMGA volunteer Kim Lesperance for forwarding the following information that she discovered while doing some important research for her own project.


Though “clinging” and “vine” seem like a wedded concept, only a few vines really do hold on that way, using aerial rootlets that act as suction cups to attach themselves to their support. These rootlets are very strong and enable even very heavy vines to rise high on flat walls. Examples include climbing hydrangea, Boston ivy, and English ivy.

More commonly, vines are inclined to twine, wrapping their main stems around the nearest available support and circling it as they grow. Examples include beans, morning glories, bougainvillea, hops, hoya, and wisteria.

The other large group are tendril-climbers, which send out specialized, leafless stems


My clematis in glorious bloom last summer

that wrap tightly around any adjacent object that’s thin enough to get a grip on. Examples include peas, cup-and-saucer vine, grapes, passionflower, and porcelain vine. The specialized stems that do the holding on can also have leaves, in which case they’re called petioles. Clematis are the best known petiole users, but Climbing Snapdragons (asarinas) also climb this way, and so do those rare nasturtiums that genuinely climb.


My trumpet vine last fall climbing over the arbor. It pretty much goes where it wants to and requires a firm hand.

But not all vines do genuinely climb. Some just head for something supportive and grow on, around, over, or through it, sending out a tendril or two, applying a rootlet, or twining a bit without behaving in and recognizably organized way. Expect to receive some guidance if you plant these and have a particular direction of growth in mind. Examples include trumpet vine, silver-lace vine, and some of the jasmines.

The Hydrangea


My climbing hydrangea has filled out the fence nicely

I love my garden and there are particular favorites:  peonies, astilbes, feathery yarrow…but nothing compares to the hydrangea for me. I have different varieties scattered in my flower beds, and one bed dedicated entirely to hydrangeas. After waiting patiently for the last 5 years, my climbing hydrangea (which has done an incredible job of growing along the fence) FINALLY has a teeny, tiny little blossom on it this year. I almost feel like a new parent! Can’t wait to see it in bloom!

Many people share my love of hydrangeas. I found this really nice article from Georgia Raimondi, in her book “The Passionate Gardener.”

The Hydrangea

Long after the petals of my spring-flowering shrubs have faded, 
my hydrangeas begin to bloom and fill the garden with billowy 
blossoms of sky blue, rosy pink, and creamy white. This old-fashioned
plant with branches laden with voluptuous blossoms graces many summer
gardens where it produces armfuls of flowers. Hydrangeas lend an air of 
gentility to a garden, and their long-blooming flowers also provide
spectacular color throughout all the hot days of summer.

The name hydrangea is derived from the Greek words for water (hydro) and
bowl or vessel (angeion). But my first hydrangea made me think of another
word derived from Greek: chameleon.

A friend in the fashion industry gave me my first hydrangea. She had
selected a specific plant because its glorious color recalled a particu-
larly shocking pink that we had discovered on a trip to Paris. But imagine
my shock next season when my hot pink plant produced blooms of heavenly
blue. After some research I discovered that this striking metamorphosis was
not due to hocus-pocus but to a chemical interaction between the soil and
the plant. Acidic soil encourages the hydrangea to absorb aluminum which
accounts for its blueness. When the soil is more alkaline, aluminum absorb-
tion is prevented, and pink blooms abound. Mopheads -- the type my friend had 
given me -- are the least stable of the hydrangeas and most readily change
color according to the pH of the soil.

Thus enlightened, my shock gave way to delight, and hydrangeas have since 
become a stalwart of my garden. Their luxurious blossoms are quite hardy --
I leave some on the bush through the winter to hold an echo of summer through
the year. The cut flowers respond well to drying, and add texture and richness
to arrangements and wreaths. At Christmas, they make attractive and unex-
pected ornaments on the tree.

There are more than 500 hydrangea cultivars including various climbers and
shrubs with diverse foliage and flowers. With so many elegant choices, you
are sure to find a botanical chameleon of your own to enhance your garden with
its extravagant blooms, air of old-fashioned gentility, and chromatic magic.

Planting Tips

Lush shrubs of macrophylia hydrangea with abundant blooms are easy to
***Happiest in morning sun but will also flower abundantly in light shade
***Will thrive in almost any well-drained soil.
***To manipulate color, remember that deep blue results from acidic soil
((pH between 4.0 and 5.5) and rich pink from alkaline (7.3 to 7.5). Increase
alkalinity with cautious additions of lime. Increase acidity with peat moss,
aluminum sulfate, or sulfur. (Pee gee hydrangea slowly turn from white to
soft pink to rusty bronze, irrespective of the soil's pH).

The teeny, tiny little bud that has finally appeared on my climber!